A NIOSH investigation of a medical cannabis facility identified several engineering and administrative controls to help reduce potential occupational exposures to cannabis components such as delta-9 tetrahydrocannabinol, delta-9 tetrahydrocannabinol acid, cannabidiol, and cannabinol. Surface wipe samples collected throughout the facility, which included an indoor and outdoor grow operation, detected concentrations of all these components. NIOSH’s health hazard evaluation report (PDF) notes that the health implications for occupational exposure to these components are unknown. Agency staff also identified diacetyl and 2,3-pentanedione in screening air samples, but those results were deemed inconclusive due to the differences between the two sampling and analytical methods used during the evaluation: the partially validated evacuated canister method and the standard, validated OSHA method. According to NIOSH’s HHE report, none of the exposures to diacetyl or 2,3-pentanedione in the air were at or above the lowest occupational exposure limit for full-shift air samples.

Further air sampling for microbial biodiversity found exposures to microbial fungus and endotoxins. These exposures can increase employees’ risk of allergic and respiratory symptoms.

NIOSH recommends that the employer install local exhaust ventilation to reduce exposures, especially during grinding operations. The agency also suggests moving the decarboxylation process to a seldom-occupied area in the facility to prevent unnecessary exposures to diacetyl and 2,3-pentanedione. (The report explains that decarboxylation is achieved through aging or applying heat to cannabis.) The employer should limit access to the areas where higher exposure tasks are occurring and develop a cleaning schedule to remove cannabis components from work and tool surfaces.

Read the full HHE report (PDF) to view all of NIOSH’s recommendations.